Using a pipe within a bash alias

Question

I don't have experience in shell scripting, so I'm unable to see the problem of the following situation:

I have defined an alias of the following form(file.c is located in ~/dir):

alias code="cd ~/dir | vim file.c"

When inputting it, I get the following warning, and the proper files aren't opened:

Vim: Warning: Input is not from a terminal
2 files to edit

I thought that the pipe operator in this instance would separate the two commands, first changing the directory, then opening the file.

Answer 1

Since you mention you don't have experience in shell, I will be verbose.

The problem is that you are using the pipe wrong.

cmd1 | cmd2

Means redirecting the output of cmd1 to the input of cmd2. Maybe you are confusing it with the OR operator ||, which can be used as:

cmd1 || cmd2

"If cmd1 is not successful, execute cmd2". This would not help you in your case, though. Both previous answers work for you:

alias code="cd ~/dir; vim file.c"

Using the semicolon, which is just a simple command separator. Or my personal favorite

alias code="cd ~/dir && vim file.c"

Which uses the AND operator.

cmd1 && cmd2

means "do cmd1. If it is successful, proceed with cmd2. Otherwise, stop".

Answer 2

A better alias would be:

alias code="cd ~/dir && vim file.c && cd -"

This will ensure you are not opening file in your current directory if cd failed and return to the old directory where you were.